Control mechanism



y 1934. R. L. MAURER 8,3

CONTROL MECHANISM Filed Sept. 14, 1928 3 Sheets-Sheet l E @7316? B433aura? afWMz/ w July 31, 1934. R L, MAURER 1,968,302

CONTROL MECHANISM 3 Sh et Filed Sept. 14, 1928 eat 3 Patented July 31,1934 iststz:

CONTROL MECHANISM Russell L. Maurer, Chicago, Ill., assignor toGrigsby-Grunow Company, Chicagmllh, a corporation of Illinois; Frank M.-McKey, receiver in bankruptcy Application September 14, I928, SerialNo. 306,083

11 Claims.

My invention relates in general to control mechanisms. It has to do moreparticularly with a method of and means for controlling the position andadjustment of apparatus which is located at some distance from thecontrol point.

My invention as shown in the herein described embodiment is directedparticularly to the control of a radio tuning apparatus. It presupposesthe location of a speaking unit or speaking units at some distance fromthe receiver, and the tuning of the receiver from the location of thespeaker.

In home installations, particularly where I the residence is unusuallylarge, it is often desirablev to use a single receiver of a goodquality, with a i number of speakers located at different points, forexample on a porch,.a living room, and a bed room. As now arranged it isnecessary to go.

to the set not only for tuning the receiver itself, but. also very oftenfor connecting the speaker.

-Another example of the location of a radio re-' ceiver at some distancefrom the speaker is where the speaker must be placed in some locationwhere there is considerableinterference, and then in order to avoid thisinterference the re- ;ceiver is placed in a quiet area and a relativelylong cable carrying the voice frequency current is run to the speaker.

Accordingly the principal object of my present invention is theprovision of an improved method or" and means for controlling themovement of apparatus at a distance removed therefrom.

Another object is to tune a radio receiver from a distant point.

Another object is to provide a radio receiver with a speaker located ata distance therefrom and a tuning mechanism located at both the receiverand speaker.

Another object is the provision of an electrically controlled switchmechanism for turning a radio dial shaft.

Another object is the provision of such a mechanism mounted to controlthe dial shaft, and in combination therewith means for controlling a-Vernier or similar member.

Another object is the provision of a .tuning mechanism located at adistance from the re-- Other objects and features of the invention willbe apparent from a considerationof the following detailed descriptiontaken with the accompanying drawings wherein Fig. 1 a plan view of themechanism employed in one embodiment of my invention, and showingthemanner in which it is attached to a radio receiver;

Fig. 2 is a view taken along the line 2-2 of Fig. 1showing the way someof the mechanism operates;

Fig. 3 is a similar view taken along the line 33 of Fig. 1;

Fig. 4 is a fragmentary plan view of the mechanism as employed at thedistant controlling station;

Fig. 5 is a face view thereof ;v I Fig. 6 is a diagram ofa simplifiedform of circuitwherein the dial setting is now shown at the distantcontrol point, and v Fig. '7 isha diagram of the preferred form ofcircuit.

I have illustrated my invention as applied to turning the usual dialshaft to which are con-. nected a number of variable condensers and as.now arranged I provide means for turning the dial shaft quickly in onedirection so as to reset it for operation on low wave lengths. This iscon-- trolled at the distant station by means of any suitable switch,and I prefer a simple button contact for this purpose. By means of asecond buttonthe condensers are caused to move slowly in a direction toincrease'the capacity thereof until a full capacity for tuning higherwave lengths is reached, which takes in the full tuning scope of thereceiver. In any position the movement may be stopped by simplyreleasing the tuning, or as I term it the brake release key. I alsoprovide a third key which causes a'slight backward movement of the dialshaft with a consequent slight decrease incapacity, which is of value ifthe condensers are permitted to turn slightly too far when employing thebrake release key. There are other. features associated with and formingpart of my invention but these will appear as the detailed descriptionprogresses.

Referring now to the drawings I show a fragmentary portion of a radioreceiver. including a front panel 10 and a dial shaft 11 shown as theusual rotor shaftof a variable condenser with rotor plates 12 adapted toturn therewith and cooperate with stator plates 13 held by a frame. 14for the purpose of varying the capacity and modifying the tuning of thereceiver. The tuning mechanism A I show as adapted to be secured to thestandard radio tuning-shaft, and this comprises a frame 16 secured tothe front panel by. screws 17. A coupling 18 sets around the end of theshaft 11 and is tightened thereto by a set screw '19.: This couplingforms a continuation of shaft 21. which is journaled in a part of theframe and has connected thereto the hub of a gear 22. It is through thisgear that all of the movement in either direction is imparted to theshaft 21 for transmission to the shaft 11.

As previously described the first movement of the mechanism is aso-called reset movement which takes place relatively quickly to turnthe condensers to substantially zero capacity. In carrying out thismovement I employ a solenoid 23 having a plunger type of armature 24pivotally connected to a link 26 which is connected to the short end ofan arm 27. This arm 27 is loosely mounted on a shaft 28, the ends ofwhich are journaled at 29 and 31 in the frame 16. It is also secured tothe hub of a gear 32 which is also journaled on the shaft, and this gear32 meshes with the gear 22 so that movement of the arm 27 serves to turnthe shaft 11. Consequently energizing the solenoid 23 will lower theplunger 24 and turn the arm 2'7 about its pivot in such a way as toreset the condensers to zero reading.

In tuning the variable condensers from the re-' set or zero capacityposition the rotor plates are moved gradually to increase the capacityuntil a maximum possible capacity results. At any time in this gradualtravel of the condensers the movement thereof may be stopped. I shallnow describe the mechanism with which I accomplish this result.

In the first place the rotor plates are arranged on the rotor shaft sothat they will naturally tend to move by gravity to a lower position.This is accomplished by connecting them off-center as is the usualpractice, the off-center position being preferably the same which willresult in a constant or even dial graduation. This has a tendency tocause the plates to move as they are reset and to further bring aboutthis result I provide a weight 36 on the free end of the arm 27,

- this weight being threaded on to the arm so that it can be adjustedback and forth in a manner to be described, and a pair of locking nuts37 and 38 are provided at both sides thereof. A cap 39 is threaded on tothe extreme end of the arm 27. v to protect the threads and also toperform a certain function which will be described. It is obvioustherefore that with the weight of the rotor plates and the added weightof the weight mass 36 the rotor plates will be returned to a fullcapacity position. In order, however, .to regulate the.

speed at which this takes place I provide a regulating movement whichwill now be described.

Secured on the shaft 28 is a ratchet gear 41,

and a ratchet 42 pivoted to the arm and spring 7 pressed against theratchet gear teeth by a spring 43, causes a rotation of this ratchetgear as the arm 27 moves through the influence of the weight 36. A spurgear 44 is also secured to the shaft 28 by a pin 46 and meshes with asmaller gear '47 carried by a shaft 48 which is journaled in bosses 4949carried by aframe. This shaft 48 also has a larger gear 51 which mesheswith a gear 52 carried on a shaft 53 also transverse of ,the frame andjournaled in bosses 54--54. This shaft carries a fan type of regulator56which through the resistance offered by the air limits the speed atwhich the arm 27 is turned.

In order to permit turning of the arm 27 when occasion requires, Iprovide a braking mechanism which is shown in the form of a brake wheel57 carried by the shaft. 53 and adapted to be engaged by a brake shoe58.. This brakeshoe is carried by an armature 59 which is pivoted at 61and held in a position to engage the brake wheel with the brake 58 by aspring 62*. Im-

mediately below the armature 59 is an electromagnet 63 which is adaptedto be energized and attract the armature 59 so as to release the brakeshoe'58. Secured to the brake shoe is a stop pin 64 which is adapted toengage the blade 56 and thus positively arrest the movement of theregulating movement when the armature 63 is deenergized.

It will be recalled that I also provided mechanism for causing a slightbackward movement of the tuning mechanism and I accomplish this byoperating the reset solenoid 23 so as to draw the entire mechanism in areverse direction, but simultaneously with the operation of thismechanism I provide means for limiting the movement so as to obtain onlya slight backward movement instead of a full reset movement. I accom'-plish this by means of the following mechanism.

Immediately below the electromagnet 63 is a second armature 66 which ispivoted at 6'? and has its free end extending between a pair ofbifurcations 6863 on the end of a bell-crank lever 69. The bell-cranklever is pivoted to a stud shaft 71 which is adjacent to a ratchet wheel73 formed integral with the reset gear 32. The upwardly extending arm ofthe bell-crank is formed in two sections with a pivot 74 between themand with a spring 76 tending to hold the upper point 77 in a straightposition. This construction is to accomplish certain functions whichwill be described in connection with the operation of the mechanism.

In the type of installation which I prefer I arrange to show the dialsetting, that is the frequency or wave length to which the receiver istuned, at the speaker station. To accomplish this the control mechanismis repeated at the speaker station but, as shown in Fig. 4 a dialindicating hand 78 carried by a small shaft 79 is secured to thecoupling 18 in place of the condenser shaft ll. In this connection thereset mechanism may be housed within any small type of cabinet with apanel 81, and the shaft 79 extends through the panel 81 in the mannershown so as to point to suitably provided gradua- 120 tions 82 carriedby the panel (Fig. 5).

Operation of the main control mechanism In the operation of themechanism for tun-'- ing a receiver a button contact is closed supplyingcurrent to the solenoid 23. This draws down on the plunger 24 thusraising the weight 36 as well as raising the heavy ends of the rotorplat-es 12'. As this is done the ratchet 42 is permitted by the spring43 to ride the ratchet wheel '4l so that the speed control mechanism isnot affected at all during resetting. The brake 58 and stop pin 64 arein engagement during this operation. The condensers are now arranged atzero capacity.

In the next step'in tuning, a contact is closed energizing the solenoid63. This draws the brake 58 away from the brake wheel 57 and alsoremoves the stop pin 64 from engagement with the blade 56. This permitsthe downward move- 140 ment of the weight 36 to operate the condensershaft through the gears 32 and 22 and through the shaft 21, thisdownward movement being aided by the weight of the condensers themselvesin my preferred form. This downward move- 5 ment is allowed to continueuntil the proper dial setting is reached, and until the station desiredis tuned in. During this time the armature 66 is also drawn upwardly sothat the point 77 engages the teeth of the ratchet gear 73. The

spring 76, however, allowsthe point '77 to move about the pivot '74 andthe ratchet wheel is permitted to move by the point '77. In this way themovement of the bell crank '69 is not efiective to hold the mechanismfrom turning.

Now when tuning it is always possible that the movement of the condenserplates is allowed to go too far and in this case another contact isclosed which passes current to both the solenoid 23 and theelectro-magnet 63. When these are energized the plunger 24 immediatelystarts to move and through the mechanism'shown the rotor plates alsoimmediately start to move. This immediate or initial movement is alsoimparted to the lever 66, but on account of the space between thebifurcations 68 this movement is not immediately effective as regardsthe point '77. Therefore the wheel '73 will have moved a portion of agear tooth before the point '77 has gone in to engage against theratchet gear, and accordingly movement equivalent to the width of onetooth only is permitted by this action. Obviously, however, the partscould be adjusted to permit a greater movement if desired.

.The circuit Reference is first made to Fig. 6 in which a simple form ofcircuit is shown wherein he reset mechanism proper is employed at thespeaker station. This illustrates any usual form of receiver B with agang condenser C and adapted to be supplied with any suitable type ofcurrent as for example the usual alternating current which is suppliedto a suitable power-pack I) as shown. In this diagram I illustrateschematically the reset solenoid 23 and the brake electro-magnet 63. Twospeaker stations E and F are shown which being in all respectsduplicates'oi each other only one will be described as this sufiices foran understanding of them both.

At the speaker station E'key button switches 86,

8'7 and 83 are provided, controlling the reset, brake release, andreverse'rotation movement of the mechanism. A battery 39 representingany suitable source'of power is provided to control the operation of themechanism at the speaker. The key 86 is adapted to be'closed to energizethe solenoid magnet 23, the circuit'through this switch including simplythe 'two contacts thereof, the

solenoid windings '23 and the two terminals of the battery 89. The keyswitch 8'7 is closed to energize the solenoid 63 and the closing'of thisswitch simply places the switch, solenoidwindings, and battery 89 inseries. tion of the key 88 this has three contacts, namely, the upper orkey contact, and two lower contacts 88' and 88". The two upper contactsof the switch lead to one side of the solenoid windings 23 and 63respectively, while the lower terminal 88 is common, extending to oneterminal of thebat tery, While the second terminal of thebatteryiscommon to both of the solenoids. For this reason when contact is formedbetween the two upper terminals there is no current flowing, thisoccurring only when the lower terminal 83'" is cut into As to theopera-' the-speaker may be regulated; Switch 95 is provided fordisconnecting the speaker at the location thereof without disconnectingthe set itself. v

It will be obvious that I provide a small switch 96 in the commercial A.C. line adjacent the solenoid 23. This is a spring contact type ofswitch which is adapted to be engaged by the end 39 of the arm 2'7 sothat when this arm is in its lowermost position this switch will be openand accordingly cut off the flow of current to the receiver. In this waythe set itself may be put out of operation at the location of thespeaker by simply holding the brake release key until the arm 2'7 dropsto its lowermost position and interrupts the commercial current input tothe set.

While present day commercial radio receivers are all provided withso-called single dial control, practically all such receivers also havea Vernier or fine tuning attachment of some type or other which isemployed for. bringing in stations which are not brought in withsatisfactory clearness by the usual single dial. These stations areusually distant stations, since all of the bet-. ter classes of sets nowobtain practically perfect single dial tuning'for all local stations'inthe 16.3; vicinity of lm'ge cities. For the purpose of accomplishingthis I provide a switch mechanism G wherein a plunger is provided withina solenoid and the attraction of the plunger is arranged to beproportional to the input of current, which 155 input is controlled by arheostat or potentiometer located at the speaker station. I may providevarious specific arrangements to bring about this. result but thearrangement which I showappears to me at the present time to be the mostsatis- 11o. factory. This consists of a pair of solenoids 96 and 97arranged with their poles reversed and having. a plunger 93 disposedwithin the two solenoidsand having a plunger rod running to anysuitable; mechanical contrivance for efiecting the Vernier 11 tuning.-With this arrangement I obtain a pushpull or two way movement of theplunger which does not depend upon the use of springs, etc., to returnit to position. I

I also provide a novel type or" switch for controlling the currentsupplied to the solenoids, this being arranged so that the power is cutoff and the resistance taken out of series. This switch: comprises aresistance winding 101, with termi na s 102 and 103. center terminal104: adapted to contact with the winding 191, and a second pair ofterminals. 106 and 10'? adapted to contact with the terminals 162 and103 respectively. I ar ange the movable portion of the switch so that itmay be forced-l by the action of a suitable spring or the like away.from engagement with the winding 101, so that when the plunger 98 is tobe moved the switch is. moved to connect the terminals described and soplace the winding 101 in the circuit. The electrical connections in theoperation of this switch include a lead 168 common to opposite sides of?the two solenoids and leading to one side of the battery 89. Theopposite side of the battery is connected through a common lead 169 anda terminal 111 to the switch terminal 104. The opposite ends of thesolenoids 95 and 97 are connected to the terminals 197 and 108respectively,

so that with this arrangement operation of the switch arm and terminalarm lu-i serves to in Iii-t crease the flow of current in one solenoidwhile decreasing it in'the other, and this action can 1 be carried on tosuch an extent as to practically cut off all flow of current in onesolenoid, (this 'depending' upon the resistance of the winding lit.

The switch also includes a 101) or supply the full current to the othersolenoid. This is responsible for the full movement which may beimparted to the plunger 98 in either direction.

In Fig. 7 a complete circuit, which I now con sider as the best toemploy with the preferred embodiment of my invention is illustrated. Forthe purpose of explanation I employ the same letters of reference asnear as possible in this circuit as employed in the other figures. Thetwo speaker control stations which are shown here I designate by thecharacters H and I to distinguish them from the stations E and F shownin Fig. 6. It is to be observed that the circuit of Fig. 7 is employedwhen a controlling mechanism is placed not only at the receiver, but ateach speaker station, so that a dial 7 8 with graduations 82 is visibleat each speaker station, so that the frequency to which the receiver istuned is shown at the speaker station. At the speaker station thereceiver 13 is shown as in Fig. 6 with the same arrangement in the gangcondenser C, power-pack D, A. C. current supply, etc. The solenoids 63and 23 are the same as is also the battery 89. The switches 86, 87 and88 are of the same character as is also the switch arrangement employingthe resistance 101 for controlling the tuning member G.

Referring now more fully to the distant station H, in actual mechanicalarrangement a unit exactly the same as that employed at the receiver maybe used. This is hooked up when employed at the speaker station in themanner shown in Fig. 4. This employs a pair of solenoids which Idesignate 6311 and 23H respectively which are the same as the solenoids63 and 23 and operate the brake and reset mechanism respectively. Aswitch 96H is also employed but instead of cutting off a source ofalternating current supply as happens in the receiver, this switchserves to extinguish the filament of a lamp 112 which is connectedthrough the switch 96H to the battery 89 and is therefore lit while thereceiver is in operation. The use of this light therefore not onlyserves to make it possible to employ exactly the same construction inboth places but it serves the additional purpose of furnishing a dialillumination and at the same time indicating positively when the radioreceiver is disconnected from the source of commercial supply, that iswhether or not. it is in operation.

The station 11 is provided with a plural contact switch J which carriescontact elements 113, 114, 115, 116, 117, 118, and 119. The terminals115 and 116 are the main or operating terminals of the switch and havedisposed between them a switch bar121 which serves to force theterminals 115 and 116 outwardly and thereby close all of the terminals.This completes all of the circuits except as interrupted by the switches86, 87 and 88 through the operation of which, however, the circuits arecompleted and the adjusting mechanism operated.

.The circuit is arranged so that by closing any one of the controlswitches the solenoids 23 and 23H are each connected in series with thebattery 89 so that both operate at the same time and to the same extent.Considering the operation of the control switches and the establishmentof the circuits for energizing the solenoids,

;-the closing of the button switch 86 serves to energize the solenoids23 and 23H. The circuit thus established extends from the positive sideof the battery 89 through conductor 126, to contact 118, contact 119,through switch 86 to the conductor 127, through the solenoid 23 and backto the negative side of the battery through conductorv 128. Anothercircuit is established from the posi: tive side of the battery throughconductor 1126,; terminals 118 and 119, switch 86 to conductor 127, tothe solenoid 23H to terminals 114 and 115 and back to the negative sideof the battery through conductor 128.

Other circuits including the solenoids 63 and 63H are establishedthrough the operation of the switch 87. The first of the circuits socompleted extends from the positive side of the battery throughconductor 126 to terminal 118, thence to terminal 119, through theswitch 86, to conductor 129, through the solenoid 63 and back, to thecommon negative conductor 128 to the negative side of the battery.Another circuit is also established which is traceable from the positiveside of the battery through the switch 87 in the same way to theconductor 129, and thence through the solenoid 6311 to the terminal 113and, contact having been established between terminals 113, 114 and 115by the operation of the switch J, return is made through the terminal115 to the negative conductor line 128. V

In operating the switch 88 the same eifect is obtained as if theswitches 86 and 87 were operated simultaneously. To obtain this effecta'conductor 131 is connected from the upper terminal of this switch tothe conductor 127 and another conductor 132 interconnects the terminal88' and the positive line 129 leading to the brake reset solenoids. Theterminal 88 is common to the two lower terminals in the switches 86 and87 and leads to the terminal 119 so that actuation of the switch 88obviously serves the same purpose as closing the switches 86 and 87. Inthis connection it is to be observed that since the common terminal 88"is positioned at the bottom and is the last terminal to form contactthere is no possibility of getting current in one of the solenoidsbefore the other.

In the station H I provide a usual type of speaker with a volume controlthereon all arranged substantially the same as in the simple circuitarrangement of Fig. 6, and in Fig. 7 I employ the same referencecharacters. This speaker is connected to the set by the operation of theswitch J through the actuation of the switch arm 121. The speaker hasone terminalv 134 leading to one of the voice frequency. conductors 93,while the other speaker terminal 136 is connected to the terminal 116.When the switch J is operated this terminal 116 makes contact withterminal 117 and a conductor 137 inter-' connects this terminal and theother voice frequency conductor 92. This throws the speaker intoimmediate operation when the switch is closed.

As previously described the lamp 112 is operated through the switch 96Hand this switch is closed at all times when the dial has a numbersetting, that is to say the switch is closed at these times, but whenthe dial setting is zero the switch is opened. In order to supplycurrent to the lamp 112 I provide a conductor 138 leading from thepositive'side of the battery through the-com ductor 126 to the switch961-1, and then e to the lamp 112 while a second conductor 139 extends;from the other terminal of the lamp to the negative side of the batterythrough the conductor 128.

I employ controlling mechanism such as shownin Fig. I. connected to thedial shaft of the receiver, and an identical mechanism at each speakerstation. These are connected for control by means of the circuit shownin Fig. 7. Assuming that the operator is at the station H and has no wayof knowing whether or not the set is operating at another station, or infact if the radio receiver is in operating condition. He-starts in bylooking at the lamp 112 and if this is lit he knows that the set E is inoperation. He then moves the switch arm 121 and if the speaker 92 isheard it is fair to assume that another speaker is going in a differentpart of the'house. Generally the operator is in a position to know thecircumstances connected with the operation of this other speaker and ifhe does not desire todis-, turb the program he can simply listen in; Ifthe set is closed ofi" when he reaches the station he simply operatesthe keys 86, 87 and 88 in the mannerdescribed to tune in his program. Ifhe is thoroughly familiar with the frequencies on which the variousstations operate and knows the stations he wishes to tune in he canjudge entirely by the dial setting which as explained will be the sameas the dial setting in the receiver. When he is finished with hisprogram and wishes to cut the set off entirely it is simply necessary tohold the brake release key 87 until the arm 27 drops down sufiicientlyto open the switch 96. He can tell when this takes place becausesimultaneously the light 112 will be extinguished.

The keeping of the various stations and the receiver in synchronism is adistinct problem and this is taken care of in'the following way. Tobegin with the various adjusting mechanisms A are arranged so that theywill operate in full sequence. thelocation of the weight 36. When thesemechanisms are timed to operate in unison then from a single station thedials may be operated from any position and at any time and the stationand receiver will be in synchronism. But the operation of station H, forexample, will have no effect on the mechanism of station I; so that ifthe receiver has been controlledfrom station H and the operator thenrepairs to station I where he Wishes to tune the receiver his dialsetting at station I will probably not be the same as at the receiver.

He can tune the receiver by depending entirely on the sound emitted bythe speaker without regard to the dial setting. But it may be necessaryand advantageous to have station I and the receiver in full synchronismto get the best tuning results. This is done by pressing'the reset keyand holding it longenough to be sure that the arm 27 at the receiver andthe arm27 at station I are both in their reset oreXtreme counterclockwise position. This establishes the stations in full synchronismagain and tuning can be taken care of by viewing the location of thedial.

In tuning I also make frequent use of the switch G wherever necessary. Asmall potentiometer dial is placed on the speaker station cabinet so Iarranged that when it is pressed inwardly and i turned the switch G canbe moved in the manner lustrative, however, as anysource of current maybe supplied. It is not advantageous, however, to

employ current from the power-pack D when the switch 96 is used,becausethen if this switch were opened it would be impossible to put thereceiver in operation from a distant station point.

This is done principally by adjusting -In constructing the stations Iprefer to employ a plural contact switch such as shown at J becausebythis means I am able to put the Whole station including the speaker inoperation by means of a single switch. I am also able to controlthe'circuits so that when a set is being operated from one stationaccidental interference with the button contacts 86, 87 or 88 at otherspeaker locations will have no effect upon the tuning of the receiver;In other words the switch J must be operated before the operation of thetuning buttons will have any effect whatsoever.

I have spoken-of arranging the condensers so that with a zero settingand with the reset sole-- noid operating the rotor plates and separatedfrom the stator plates their zero capacity results.

The arrangement of the condenser plates and.

other things, however, may make it advisable to reverse this and resetthe condensers to maximum capacity while gradually decreasing thecapacity as the brake release key is pressed. This, however, is a matteror" obvious arrangement and can be determined in accordance'with theconditions found.

Among the advantages connected with the use of my invention in additionto those already pointed out I wish to state that the wiring is soarranged that additional speaker stations may be added on without makingit necessary to change any of the previous installation or even theWiring in any way whatsoever. The conductors 128, 126, 127 and 129 aresimply extended to the new station, together with the conductors 92 and93 carrying the voice frequency current. The connections made to theseconductors in connection with the operation of the newly installedstation are obvious.

One of the principal advantages I see in the use of my invention ismaintaining the receiver proper in' such a position that it cannot betamperedwith by inexperienced operators. For example in furnishing anapartment house I anticipate the possibility of providing a radioreceiver with each apartment, the receiver itself being placed on theroof or any other suitable separate place, with a distant controlstation and speaker in the apartment. In this way the tenant would havefull control of the operation of the set but would be unable to mutilateor mistreat the receiver itself in any way. With a number of receiverslocated at a single advantageous point all of them could be veryeconomically serviced whenever necessary. I

A similar idea can be carried out where it is not desirable to place thereceiver in a particular 10- cation on account of interference, steelbuilding construction which might interfere with receipt of carriercurrents or the like. Another thing where it is desirable to employ anoutside antenna and the lead-in would have to be very long, the receiveritself could be placed immediately adjacent the antenna and theconductor leading intothe speaker location would carry voice currentinstead of the high frequency current. Obviously the losses, etc. wouldbe a very great deal less with the relatively long voice frequency lineinstead of the long radio frequency lead-in.

While I have described a great many details of my invention to make theoperation clear to those skilled in the art, it is obviousthat I do notrestrict myself to any of the details shown and the inventionis limitedonly by the scope of the appended claims. 7 What I claim as new anddesire to Letters Patent of the United States is:

protect by 1. In a radio receiver provided with a tuning shaft forchanging the adjustment of tuning apparatus between two extremepositions, means for turning said shaft relatively quickly to oneextreme position, means including a governor for turning the shaftrelatively slowly to the opposite extreme position, and means operableon said second means to stop the turning of the shaft at any selectedposition.

2. In a radio receiver provided with a tuning shaft for changing theadjustment of tuning apparatus between two extreme positions, means forturning said shaft to one extreme position, means for turning the shaftto the opposite extreme position, a governor for limiting the speed ofturning in said opposite direction, operable on said second means tostop the turning of the shaft at any selected position, and means forturning the shaft a short distance in a direction opposite to thedirection in which the shaft is turned by the slow turning means.

3. In a radio apparatus a tuning shaft for changing the adjustment ofthe tuning apparatus, shaft turning mechanism for turning said shaftcomprising an operating shaft provided with means for connecting it tothe shaft to be turned, a pivoted weighted arm, means for turning saidarm relatively quickly to raise the weighted end, an operable connectionbetween the arm and operating shaft so that said shaft is turned withthe arm, releasable means for holding the arm with the weight in anelevated position, and regulating mechanism to lessen and control therate of fall of said arm when the holding means is released.

4.In a radio apparatus having a tuning shaft for changing the adjustmentof the tuning apparatus, shaft turning mechanism for turning said shaftcomprising an operating shaft provided with means for connecting it tothe shaft to be turned, a pivoted weighted arm, means for turning saidarm relatively quickly to raise the weighted ing and regulating meansincluding an electro-- magnet operable at a distance from the mechanismso that the operator may be at any distance from the shaft turningmechanism.

5. In a radio apparatus a shaft carrying a tuning element for saidapparatus, shaft turning mechanism for turning said shaft comprising anoperating shaft provided with means for connecting it to the shaft to beturned, a pivoted weighted arm, means for turning said arm rela tivelyquickly to raise the-weighted end," an op-' erable connection betweenthe arm and operating shaft 'so that said shaft is turned with the arm,releasable means for holding the arm with the weight in an elevatedposition, regulating mechanism to lessen and control the rate of fall ofsaid arm when the holding means is released, and

means for limiting the reset movement'of the arm so that a slightbackward movement of the operating shaft may be obtained.

6. In a radio apparatus a shaft carrying a tun- "ing element, shaftturning mechanism for turning said shaft which comprises an operatingshaft equipped with means for securing it to ashaf t to be turned, meansfor turning'the shaft against a" loadto a reset position representingoneext'reme' of movement of the shaft, a brake mechanism for holding theshaft against the load in any selected position, means for releasingsaid brake to permit the shaft to turn, and regulator mechanisr n'to:maintain said shaft movement at a regular rela tively slow speed.

'7. Inaradio apparatus a shaft carryinga tuning element, shaft turningmechanism for turning said-shaft which comprises an operating shaftequipped with means for securingit to a shaft to be turned, means forturning the shaft against a load toareset positionrepresenting"oneextreme of movement of the'shaft, a brake mechanism for holding'theshaftagainst the load in any-se lected position, means for releasingsaid brake to permit the shaft to turn, regulator mechanism to maintainsaid shaft movement at a regular relatively slow speed, and meansformoving said operating shafta short distance in a reset direction. I8. The'combination with a mechanism as de-' scribed in claim 6, and aswitch operated-"when the mechanism is at a predetermined position toout off the supply of electrical current to said receiver. 9. In a radioinstallation a receiver, a speaker located at a distance'from thereceiver, a'turning mechanism located at the receiver and ope'rable fromthe location of the speaker to tune the receiver, a similar "mechanismlocated at the speaker, means for starting the two mechanisms from thesame point to make them operable inunison, an indicator operable at thespeaker mechanism to show the tuning position of-the' receiver, a pilotlight at the speaker which is illuminated While the receiver issupp-lied with elec' trical energy, means for cutting off the current tothe receiver when the turning mechanisms are in a predeterminedposition, and a separate ver-' cal tuning means adjustable over a rangefor selecting aparticular frequency said tuning means being adapted tohave forward and backward motions to go from one extreme position to theother extreme position, energy storing means mechanically connected tosaid tuning means, said energy storing means'having a minimum ofpotential energy therein at one extreme position of said tuning meansand a maximum at the other extreme position thereof, local meansgoverned from said control unit for causing said energy storing means totend to assume a condition of maximum potentialenergy with acorresponding extreme position of said tuning means,

means for causing a gradual transformation of movement of said tuningmeansaway from said corresponding extreme position and means gov-' ernedfrom said control unit for arresting said motion of said tuning means atany desired'position thereof only during said energy transforma tionperiod. 7

11. The structure of claim 10, wherein additionalmeans governed fromsaid control unit is provided for causing a relatively small movement ofsaid tuning means in a RUSSELL L. MAURERQ:

